Power-driven scaffold



L. E. DEMPSEY POWER-DRIVEN SCAFFQLD Jan. 1, 1952 2 SI-lEETS-ShEET ,1

Filed April 5, 1948 PIN L/o yd E. Demps y IN VENTO BY WW QW Patented Jan. 1, 1952 UNITED STATES PATENT OFFICE 2,581,176 POWER-DRIVEN SCAFFOLD Lloyd E. Dempsey, Portland, Ores. Application April 5, 1948, Serial No. 19,020

Claims. (01. 304-18) This invention relates to new and useful improvements in scaffolds and the primary object of the present invention is to provide a novel and improved power driven scaffold which may be selectively raised relative to a building structure or the like to facilitate the convenient painting, repairing, cleaning or the like of the said structure.

Another important object of the present invention is to provide a power driven scaffold including a pair of platform supporting frames and embodying novel and improved means for spacing the frames relative to a supporting structure during the raising or lowering of the frames.

A further object of the present invention is to provide a power driven scaffold including a pair of side frame members, cable drums carried by said side frame members, and novel and improved means for actuating the cable drums in an efficient manner to effectively raise or lower the frame members simultaneously.

A still further aim of the present invention is to provide a power driven scaffold that is small and compact in structure, strong and reliable in use, simple and practical in construction, neat and attractive in appearance, relatively inexpensive to manufacture, and otherwise well adapted for the purposes for which the same is intended.

Other objects and advantages reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure l is a front elevational view of the present invention, and with parts thereof broken away and shown in section;

Figure 2 is a transverse vertical sectional view taken substantially on the plane of section line 2-2 of Figure 1;

Figure 3 is a fragmentary top plan view of the present invention taken substantially on the plane of section line 33 of Figure 1, and,

Figure 4 is an enlarged fragmentary vertical sectional view taken substantially on the plane 4-4 of Figure 1.

Referring now to the drawings in detail,

wherein for the purpose of illustration, there is disclosed a preferred embodiment of the present invention, the numeral represents one of the side frame members that is used in conjunction with the present invention generally. This side frame member ID includes a pair of spacedparallel, inverted substantially U-shaped preferable angle iron sections l2 retained spaced relation by connectingbars and M which are 2 |B. The lower forward and rear ends of the sections l2 and [4 are connected by cross straps l8 and 24, respectively.

The spaced inner ends of, a pair of coaxial horizontal arms 22 are secured by welding or the like to the forward ends of the sections 12 and M. The inner spaced ends of the arms 22 are secured to the forward ends of the sections 52 and i l by angle iron 42a and the inner ends of the .arms 22 are joined by upper and lower straps 28 and 29 whose ends are fixed by welding or the like to the inner ends of the arms 22. The outer ends of the arms 22 are braced to the forward legs of the sections l2 and I4 by inclined braces i 44 and 46.

The vertical leg portions 42 of a fabricated u-shaped member are fixed by welding or the like to the rear ends of the sections i2 and I4 and the leg portions 42 are joined by a horizontal strap 26 that overlies the web 2! of the U-shaped 'member 20.

A support arm 30 is slidably received between the web 2| and the strap 26, and the arm 30 is also slidably received between the upper and lower straps 28 and 29. It is thus seen that the 'web and strap 26 form a forward guide for the arm 30 and the straps 2B and 29 form a rear guide for the arm 30.

A hat-shaped cross member 40 overlies the arm gill and is fixed, by welding or the like, to the sections l2 and I4, adjacent the forward and rear ends thereof. Horizontal angle iron arms are secured by welding or the like to the vertical flanges of the member 40, adjacent each end of the member 40, and the horizontal flanges of the arms 56 are formed with threaded apertures that receivably engage clamping screws 52 for a purpose which will laterbe more fully apparent.

The arm 30 is formed with a plurality of longitudinally spaced openings 36 for registering with an opening (not shown) that is formed in the strap 26. A locking pin or bolt 38 is extended through the opening in strap 26 and one of the openings 36- to adjust the arm 30 relative to the frame l0.

Fixed to the cross member 40 is a pair of substantially inverted substantially U-shaped supports 54 that support opposed bearings 56 in which there is rotatably mounted a driven shaft 58. A cable drum- 60' suitably keyed on the driven shaft 58 holds a cable or suspension cable 62 thereon.

Secured by rivets or the like to the web portions of the sections 12 and I4, is an anchor plate 64 to which there is removably secured 9. depending motor 66, preferably an electric motor having a conductive cord 68. A sprocket (not shown) is fixed on the drive shaft (not shown) of the motor and is connected by a link chain 10 to a driven sprocket 12 which is fixed on the driven shaft 58 for rotation of the driven shaft by the motor 66.

Welded or otherwise suitably fixed to one of the sections l2 or l4, are the ends of a substantially U-shaped wire support frame 13 that in clines upwardly and forwardly and is formed with an integral loop 14 for slidably engaging a safety hand gripping rail 16.

The numeral I8 represents a U-shaped strap the ends of which rigidly engage a connecting plate 80. Removably carried by the plate 80, is a swivel element 82 that engages an eye 8 formed at the free end 86 of the cable 62.

Operatively connected to the motor 86 is a conventional braking mechanism 88 that will stop the motor at a predetermined point during the winding or unwinding of the cable drum 50.

In practical use of the present invention, there is provided preferably two of the side frames H). A platform GE: is extended between the side frames Hi, frictionally bears upon the support arms 30 of the frames l and below the channel members 40 so that by adjusting the clamping screws 52 the platform 90 will be fixed to the side frames I0. It is preferred that the motors 65 be connected to a single outlet cord 92 which is provided with a conventional electric plug (not shown) that is inserted into a usual outlet receptacle (not shown). The safety rail 75 is extended between the loops 14 of the frames 72 for each side frame Hi, to guard a person or persons standing on the platform 90.

The strap 18 carried by each of the cables 62 is applied to a supporting structure with a hook or the like so that as the motors 66 for each of the side frames H] are actuated to drive the chains iii in one direction, the cables 62 will be wound upon the cable drums B0 to raise the side frames in with the rollers 32 carried by the support arms 3t frictionally engaging the supporting surface adjacent which the side frames are raised.

It is preferred that the rail 20 support a caster Ed and that the rail 22 support a pair of casters 9!; whereby the present scaffold construction is portable or mobile. Hand gripping bars 98 are suitably secured to the side frames and provide a means whereby a workman may support and balance himself while standing on the platform 90.

In view of the foregoing description taken in conjunction with the accompanying drawings it is believed that a clear understanding of the device will be quite apparent to those skilled in this art. A more detailed description is accordingly deemed unnecessary,

It is to be understood, however, that even though there is herein shown and described a preferred embodiment of the invention the same is susceptible to certain changes fully comprehended by the spirit of the invention as herein described and the scopeof the appended claims.

Having described the invention, what is claimed as new is:

1. A power driven scaffold comprising a pair of frame members, each of said frame members including a pair of inverted substantially u-shaped sections, guides fixed to the ends of said sections, support arms slidably received by said guides and each having a series of longitudinally spaced openings, means carried by one guide of each frame member and extendable through selected openings in said arms for adjusting the support arms relative to the sections, rollers carried by said support arms-for spacing the frame members relative to a supporting structure, a cross member fixed to each frame member and supported above said arms, a platform slidably mounted on said arms and disposed between said arms and said cross members, extensions fixed to and projecting laterally from said cross members, clamping screws adjustably carried by said extensions and urging the platform against the support arms, wire frames secured to the frame members and having looped portions, a safety rail having its ends received in said looped portions, wheels mounted on the frame members, and power means associated with each of said frame members for selectively raising and lowering the frame members.

2. A power driven scaffold comprising a pair of frame members, each of said frame members including a pair of inverted substantially U-shaped sections and guide means between the ends of said sections, a support arm slidably and adjustably carried by the guide means of each frame member, rollers carried by the support arms for riding against a supporting structure, a crossmember fixed to each frame member, said crossmembers extending between and above said guide means and overlying said arms, a platform extending between and supported on said arms, clamping means carried by said cross-members for clamping the platform against the arms, and power means associated with the frame members for selectively raising and lowering the frame members as a unit.

3. A power driven stirrup comprising a frame member including a pair of inverted substantially U-shaped vertically disposed sections having forward and rear ends, a forward guide at the forward ends of said sections, a rear guide at the rear ends of said sections, said guides having opposed horizontal openings therein, a horizontal spacer arm slidably received in said openings and having a series of longitudinally spaced openings, a roller on one end of said arm, means carried by one of said guides and extendable through one of the openings of said series of openings for adjusting the arm laterally of said guides, a cross-member overlying said arm and terminally secured to and between said sections, a cable drum supported upon said cross member, and power means overlying said cable drum supported solely by said sections and operatively connected to said cable drum.

4. A power driven stirrup comprising a frame member including a pair of inverted substantially U-shaped vertically disposed sections having forward and rear ends, a forward guide at the forward ends of said sections, a rear guide at the rear ends of said sections, said guides having opposed horizontal openings therein, a horizontal spacer arm slidably received in said openings and having a series of longitudinally spaced openings therein, a roller on one end of said arm, means carried by one of said guides and extendable through a selected enact the openings of said series of openings for adjusting the arm laterally of said guides, a cross-member overlying said arm and terminally secured to and between said sections, clamping means carried by said crossmember for clamping a platform against said arm, a pair of casters carried by the forward guide, and a singlecaster carried by the rear uide and disposed directly beneath the arm and located between said pair of casters.

5. A power driven stirrup comprising a frame member including a pair of inverted substantially U-shaped vertically disposed sections having forward and rear ends, a forward guide secured to the forward ends of said sections, a rear guide secured to the rear ends of said sections, said guides having opposed horizontal openings therein, a horizontal spacer arm slidably received in said openings and having a series of longitudinally spaced openings therein, a roller on one end of said arm, means carried by one of said guides and extendable through a selected opening of said series of openings for adjusting the arm laterally of said guides, a cross-member overlying said am and terminally secured to and between said sections, clamping means carried by said cross-member for clamping a platform against said arm, said forward guide including a pair of coaxial arms, a pair of casters carried by the coaxial arms, a single caster carried by the rear guide and disposed directly beneath the arm, a cable drum supported upon the cross-member, and a motor supported solely by said sections and operatively connected to said cable drum, said motor being supported directly above said cable drum.

LLOYD E. DEMPSEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 284,308 Klein Sept. 4, 1883 380,546 Bradds Apr. 3, 1888 382,252 Bowyer et al. May 1, 1888 472,406 Smith Apr. 5, 1892 2,007,294 Cischke July 9, 1935 2,008,081 Moussette July 16, 1935 2,072,355 Biebel Mar. 2, 1937 2,198,960 Deck Apr. 30, 1940 2,347,275 Merrill Apr. 25, 1944 

